1. Technical Field
The present disclosure relates to heat dissipation, and more particularly to a heat dissipation fan.
2. Description of Related Art
Heat dissipation fans are commonly used in combination with heat sinks for cooling electronic devices such as central processing units (CPUs).
Often, a heat dissipation fan includes a stator and a rotor. The rotor includes a hub and a plurality of fan blades extending outwardly therefrom. Each of the fan blades includes a windward lateral surface and a leeward lateral surface at opposite sides thereof. A permanent magnet is arranged in the hub and surrounds the stator. The stator includes a stator core with coils wound therearound. When electrical current is supplied to the coils, the fan blades, rotated by interaction of magnetic force of the permanent magnet and magnetic forces of the coils, generate airflow. A fan housing surrounding the stator and the rotor guides the airflow in a desired direction.
During operation, while the fan blades rotate, the housing is stationary, and a gap exists between the outer ends of the blades and the housing to avoid friction therebetween. Accordingly, the size of the fan blades is limited, which correspondingly limits the airflow. Furthermore, since cooling air is pushed by the windward lateral surface of each rotary blade to create airflow, an air pressure at a first area adjacent to the leeward lateral surface of each fan blade is much lower than at a second area adjacent to the windward lateral surface of the fan blade. Thus airflow from the second area to the first area via the gap increases the noise of the heat dissipation fan.
It is thus desirable to provide a heat dissipation fan which can overcome the described limitations.